Yeah, the major problem with my chosen category of folklore/urban legend is that when people retell a story (when it begins going through the folk process) they feel the need to force it to make sense. The eyewitness accounts of dancing cows and aliens bringing pancakes have an immediacy, absurdity, and realism which is lacking in the well-polished Phantom Hitchhiker narrative.
BTW, Peni doesn't actually know for a fact where the name "OZ" came from, but the story told in publicity materials during Baum's lifetime was that he was searching for a name and spotted the easy pronouncability of the label on his second file cabinet. This is certainly possible and is presumably the story Baum himself told his marketing people. However, it has always sounded to me like the sort of glib explanatory fable authors tell because other people insist on reasons and sources for artifacts that your brain threw out with no particular effort when you needed something. So much of creation happens while you're not looking that authors don't worry about it much. He needed a name and he pulled one out of the air. The air's full of stuff like that, if you're paying attention.
If you want to see someone sigh and roll her eyes, ask an author where she gets her ideas. I know people who explain about the idea tree in the back yard, or the idea store, or trading with the little gnomes who dig up the idea ore. Pullman had his garden shed (and didn't he get tired of that one!). I always say: "Same place you do," because everybody's having ideas all the time. It's just a question of whether you do anything with them, or can tell the difference between the ones with expansion potential and the one-offs.